Messages in this thread Patch in this message | | | Date | Fri, 24 Sep 2010 09:24:36 -0700 | From | Greg KH <> | Subject | [48/80] aio: check for multiplication overflow in do_io_submit |
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2.6.35-stable review patch. If anyone has any objections, please let us know.
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From: Jeff Moyer <jmoyer@redhat.com>
commit 75e1c70fc31490ef8a373ea2a4bea2524099b478 upstream.
Tavis Ormandy pointed out that do_io_submit does not do proper bounds checking on the passed-in iocb array:
    if (unlikely(nr < 0))         return -EINVAL;
    if (unlikely(!access_ok(VERIFY_READ, iocbpp, (nr*sizeof(iocbpp)))))         return -EFAULT;            ^^^^^^^^^^^^^^^^^^
The attached patch checks for overflow, and if it is detected, the number of iocbs submitted is scaled down to a number that will fit in the long. Â This is an ok thing to do, as sys_io_submit is documented as returning the number of iocbs submitted, so callers should handle a return value of less than the 'nr' argument passed in.
Reported-by: Tavis Ormandy <taviso@cmpxchg8b.com> Signed-off-by: Jeff Moyer <jmoyer@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
--- fs/aio.c | 3 +++ 1 file changed, 3 insertions(+)
--- a/fs/aio.c +++ b/fs/aio.c @@ -1667,6 +1667,9 @@ long do_io_submit(aio_context_t ctx_id, if (unlikely(nr < 0)) return -EINVAL; + if (unlikely(nr > LONG_MAX/sizeof(*iocbpp))) + nr = LONG_MAX/sizeof(*iocbpp); + if (unlikely(!access_ok(VERIFY_READ, iocbpp, (nr*sizeof(*iocbpp))))) return -EFAULT;
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